PRELIMINARY REMARKS. 
21 
stream arid warm atmosphere, fogs are generated, which 
obscure the air for great distances around. Another cold cur¬ 
rent from the Arctic sea flows inside of the Gulf stream down 
the coast of North America. It lowers the temperature of the 
coast. This effect is unfavorable upon New England, but 
favorable to the southern states situated upon the seaboard. 
These great ocean carriers, wherever they impinge upon the 
bottom of the sea, or upon a shore, deposit a part of their bur¬ 
then. The banks of Newfoundland, St. George’s bank, Sable 
island, have been made by contributions from the Gulf stream. 
While it distributes these burthens of matter, it is also a great 
distributer of heat. The climate of Europe and of the northern 
seas is mitigated by this great current carrying a warmer water 
than the surrounding ocean. As westerly winds prevail upon 
the Atlantic, the coast of New England receives only a small 
amount of the heat of the Gulf stream. 
§ 17. The Atlantic tidal wave. The ocean, under the influ¬ 
ence of astronomical forces, is acted upon in mass, and its 
waters rise in advancing or retreating waves, according to the 
position of the sun and moon, which are the positive agents in 
effecting these movements. By the rise and fall of the wave 
the detrital matter is borne forward in the direction of the 
advancing undulation. The great tidal wave of the Atlantic 
moves from south to north along the eastern coast of the United 
States, impinging upon its irregular shore, by which the 
inward terminus of the wave is retarded. It flows up the bays 
and harbors, encounters the river currents, which it retards, 
and in consequence of which the heavier portions of their bur¬ 
dens are deposited. In its onward progress to the north it is 
deflected to the east by the subaqueous banks. The easterly 
direction is continued till it passes the eastern soundings of 
Newfoundland; it then resumes its northerly course. 'To the 
interposition of an irregular coast, causing a retardation of the 
free forward movement of the advancing wave, great offshore 
and bank deposits are due; the latter of which are well known 
as the George’s and Newfoundland banks, Sable island, &c. 
